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Thread: I really need a DC/DC

              
   
   
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    Moderator Nuts & Volts's Avatar
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    I really need a DC/DC

    I need a DC/DC that will run my El Moto. Tried two different Vicor units and the first was either DOA or I killed it. Second one just limits output to 0A for some reason. Using a 12V LiPo battery at the moment, but don't have a easy way to charge it.

    My system is 70V-88V operating range. I need 12-14V output and between 100 and 200W. I won't to keep the weight and size of it really smaller. I can get a 300W Sevcon for $220 that is 2lbs, but I think there are options out there that are cheaper, more efficient or smaller.

    Let me know if you have any extra units sitting around or can get me a sweet deal

    -Kyle
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

  2. #2
    Empulse R #24 frodus's Avatar
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    I have an extra vicor (the one you turned me on to). I'm thinking maybe we need an inductor on the input to keep current from flowing from the dc-dc into the controller.

    Also have the surepower ones available.
    Travis

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    Senior Member __Tango's Avatar
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    You probably know this already, but the vicors have protection in them that will disable them when a short occurs. You have to remove all power for them to come back. That feature has saved my bacon a couple of times, but the first time it happened i thought i killed it or that it died on its own.
    EVs: 2007 Zapino Scooter, Honda VF500 Conversion (electriceptor.wordpress.com), Red Nissan LEAF SL (Arrived!)

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    Moderator Nuts & Volts's Avatar
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    Thanks Frodus, I may make an offer for that one. I'm kinda afraid I will kill another one, so I need to figure out why I suck with those before I get another one of those.

    The Surepower are a good options, overpowered for me and heavy/bigger than I want. But good price and I know it will work. That and the Sevcon will be on my list if no holy grail of DC/DCs show up for me. Sevcon is 2lbs, versus the Surepower's 5lbs, and its smaller. I'm too picky

    I solder the sense leads to the the output. Then (off the bike on a spare pack) I connect V- to Battery V- and V+ to Battery V+. When I measure the output I only get about 6V and its buzzing like its current limiting. Does it need a load to read 12V? Will a resistor properly load it?

    The new unit I have is this one (here) and it should work up to ~95V if it has the same percentage range as this one which most vicor's seem too.
    Last edited by Nuts & Volts; 25 September 2012 at 1623.
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

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    Empulse R #24 frodus's Avatar
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    Quote Originally Posted by Nuts & Volts View Post
    Thanks Frodus, I may make an offer for that one. I'm kinda afraid I will kill another one, so I need to figure out why I suck with those before I get another one of those.
    Sounds good, I have the Vicor here and ready, and I can re-order you a DC-DC.

    The Surepower are a good options, overpowered for me and heavy/bigger than I want. But good price and I know it will work. That and the Sevcon will be on my list if no holy grail of DC/DCs show up for me. Sevcon is 2lbs, versus the Surepower's 5lbs, and its smaller. I'm too picky
    Yeah, a bit larger and heavier I know...too bad there's not something cheaper that is smaller. If you DO find something, post here and let us know.
    I solder the sense leads to the the output. Then (off the bike on a spare pack) I connect V- to Battery V- and V+ to Battery V+. When I measure the output I only get about 6V and its buzzing like its current limiting. Does it need a load to read 12V? Will a resistor properly load it?
    Probably needs a load. Load it with a 12V light bulb.
    Read this? Some stuff in there to try. This wasn't intended as a standalone DC-DC for a vehicle, needs some filtering and spike protection.
    http://cdn.vicorpower.com/documents/...pps_manual.pdf
    Travis

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    Senior Member __Tango's Avatar
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    Kyle, which vicor are you looking for? we have a surplus shop close by that i haven't visited in a while that tends to carry used vicor converters for cheap (so you won't worry about destroying another one. ). If you're interested, let me know and i'll stop by to take a look.
    EVs: 2007 Zapino Scooter, Honda VF500 Conversion (electriceptor.wordpress.com), Red Nissan LEAF SL (Arrived!)

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    Moderator Nuts & Volts's Avatar
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    Travis, yea I think the problem is I just don't fully understand how these devices want to work, just how I want them to work.

    Tango, Anything with >150W output at 12V-14V output. I am also cool with paralleling two 75W units as well. Input needs to work from 63V to 87V in my application. Most Vicor's have a wide range input. I'm willing to pay up to like $70 for a Vicor because of its many advantages over other units (weight, size efficiency, etc.). I would have to know its working before I get it because I am unsure if the ones I have are DOA or not.

    I will try to test my 61V unit out again soon.
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

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    Empulse R #24 frodus's Avatar
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    I have a 75w 55-100v in 12v out and a 150w 66-160v in 12v out. I won't be using them. I paid 20 for the 75w and 50 for the 150w I think. If you want one of them let me know and I'll sell it for cost with usps flat rate included.
    Travis

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    Moderator Nuts & Volts's Avatar
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    Travis, I will most likely take the 150W unit off your hands. I want to do a little bit more testing with my current 61V unit before I jump to a new one. I'll PM you if I decide to go for it.
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

  10. #10
    Empulse R #24 frodus's Avatar
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    Sounds good. You know where I got it and what I paid. I'll throw in a matching heatsink and bussmod. Would rather someone used it than keep it.
    Travis

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